This invention is directed to an electronic timepiece battery-potential detecting circuit, and in particular, to a battery-potential detecting circuit that is uneffected by changes in the ambient temperature.
Battery-potential detecting circuits for detecting the effecting potential of a battery utilized to drive the component elements of an electronic timepiece have taken on various forms. Although an electronic timepiece is effectively driven by a D.C. battery as long as same remains above a predetermined potential, once the D.C. battery drops below such a predetermined potential, not only will the battery not provide a sufficient potential to energize the electronic timepiece, but moreover, the effective potential of the D.C. battery rapidly diminishes thereafter. Accordingly, battery-potential detecting circuits for indicating when the effective potential of the battery has dropped below a useful value have been provided.
Due to the use of integrated circuit techniques in fabricating electronic timepieces, battery-potential detecting circuits completely formed from solid state switching elements such as MOS-FET transistors have been developed. Nevertheless, because the operating characteristic of such MOS transistors are affected by changes in ambient temperature, such MOS-FET battery-potential detecting circuits have been less than completely satisfactory.